Let's simplify the expression step by step:

Simplify the numerator:
(√n/√m + √n) - (√n - √m/√n)
= (√n/√m + √n) - (√n - √m)/√n
= (√n + √n√m - √n + √m)/√n
= (√n√m + √m)/√n
= √m(1 + √n)/√n
= (√m + √mn)/√n

Simplify the denominator:
√m/√n

Divide the numerator by the denominator:
(√m + √mn)/√n ÷ √m/√n
= (√m + √mn) * √n/√m
= (√m√n + √mn√n)/√m
= √mn + √m

Therefore, the simplified expression is (√mn + √m).